Scientists Are Stumped Over Dropping Metabolic Rates — Could THIS One Thing Explain The Global Obesity Crisis?
Obesity Is The Leading Cause Of Death In The United States.
The amount of energy American and European adults expend at rest has declined significantly in recent decades, according to scientists. The surprising finding, detailed in a recent paper in the journal Nature Metabolism, may help explain why obesity only continues to get worse; although the scientists behind the research claim the reason for the decline in caloric expenditure is unclear.
Obesity is one of the main besetting illnesses of life in the modern developed world, and especially the US. According to the most recent statistics from the U.S. Centers for Disease Control and Prevention, 41.9 percent of adults are now obese, a significant increase from the 30.5 percent who were obese at the turn of the millennium. The prevalence of severe adult obesity has increased to 9.2 percent from 4.7 percent. Nearly 15 million, or 19.7 percent of US children are now obese. The estimated medical cost of obesity in the US was nearly $173 billion in 2019.
The debate about the causes of rising obesity has been further complicated in recent years by the appearance of drugs like semaglutide, known by its brand names Wegovy and Ozempic. Advocates of semaglutide and other “miracle” weight-loss drugs, whether so-called “patient-influencers” or pharma-funded doctors and race-grifting organisations like the NAACP, are doing their very best to push the claim obesity is largely beyond the control of sufferers, and only a radical pharmaceutical solution can help them shift their excess weight. With a captive audience of hundreds of millions of overweight and obese people in the developed world, companies like Novo Nordisk, the manufacturer of semaglutide, are poised to make untold billions of dollars.
The study in Nature Metabolism provides some confirmation that external changes have been taking place that may account for the growth in obesity, but it doesn’t necessarily provide support for the pharmaceutical solution. Instead, it suggests that we should try to discover what has changed to make our bodies burn fewer calories at rest, putting us at greater risk of unwanted weight gain. There is good reason to believe that exposure to harmful endocrine-disrupting chemicals, as well as changes in diet, may be responsible.
NEW STUDY: OUR RESTING CALORIE EXPENDITURE IS FALLING
Professor John Speakman, who led the international team of scientists carrying out the research, said:
"Studies of food supply suggest we are consuming more food, but working out exactly how much is difficult because people are not very good at reporting what they eat, and we can look at supply figures, but then it is a problem quantifying food waste. We have some evidence that people are becoming more sedentary, especially with a shift from manual to more sedentary occupations—but that is also only an indirect measure of how much energy people are spending.
"There is however a method for directly measuring our energy expenditure called the doubly-labeled water technique, which is a urine test that involves having a person drink water in which the hydrogen and oxygen in the water molecules have been replaced with naturally occurring 'heavy' forms, and then measuring how quickly they're flushed out."
The researchers created a database using this technique that drew on over 100 published studies, involving adults in Europe and the US. After adjusting their large-scale data set for variables like age and body composition, they discovered that total energy expenditure has declined since the early 1990s by 5.4% in women and 7.7% in men.
Professor Speakman explains:
"We expected there might be a decline, but the reason for the decline may come as a surprise.
"By combining the database measurements of total energy demands with measures of resting energy demands it was possible to establish the contribution to this decline by changes in resting and activity expenditure.
"The results showed that in fact activity expenditure has slightly increased and that the decline is all down to a reduction in the energy we spend when we are at rest."
So even though people might be more active, the additional energy expenditure of the extra activity is negated by a decrease in expenditure while resting.
At this stage, the researchers have yet to identify possible causes, but Professor Speakman believes that “one potential contributing factor is changes in our diet. We were able to see in mice that the make-up of the fat they ate affected their metabolism, but whether the same effects occur in humans requires verification.”
WHAT COULD BE CAUSING THIS? IS THERE ANYTHING WE CAN DO ABOUT IT?
Professor Speakman is right that changes to our diet are likely to be responsible, to some degree, for the changes observed in the new study. Consumption of seed and vegetable oils, substances that since the 1930s have been known to reduce energy metabolism by suppressing thyroid function, has increased inordinately over the last century, as these supposedly “healthy” fats have come to replace the traditional animal products like butter and lard that our ancestors ate. Consumption of soybean oil, for instance, has grown a thousandfold in that period.
But the Professor could go much further than he did, since we also know that we’re now being exposed to a class of chemicals called “obesogens” to an unprecedented extent. As the name suggests, these chemicals have various unpleasant effects which tend to weight gain. Reducing our exposure to them may be one of the best ways to fight obesity today.
Take BPA, for instance. When present in concentrations that are perfectly common in US waterways, this well-known endocrine disruptor (i.e. hormone disruptor) will reliably make small fish like zebrafish overeat and become fat. Genetic analysis has revealed that the chemical activates the CB1 cannabinoid gene, which is involved in regulation of appetite and satiety and also fat storage, in animals and in humans. The cannabinoid receptors are also stimulated by seed and vegetable oils.
The effects described by the recent study, however, have nothing to do with chemically induced overeating. Instead, they appear much closer to the documented effects of another class of obesogens which are known to alter the body’s tissue metabolism, reducing energy expenditure.
One such chemical is chlorpyrifos, a widely used pesticide. Scientists have shown that exposure to this chemical causes the brown-fat tissue of mice to burn calories at a reduced rate, promoting fat storage even if the mice don’t consume more calories or move less. Brown-fat tissue is a highly active form of fat that is essential for thermoregulation in the body.
Chlorpyrifos is banned in some countries, including Canada and now apparently the US, but is and has been used in huge quantities around the world. In 2014, for instance, according to its former manufacturer Dow (now part of Corteva), chlorpyrifos was used in 100 countries and sprayed on 8.5 million acres of crops.
The pesticide has been in the news in recent years in the US due to an enormous class-action lawsuit alleging that spraying in California’s Central Valley agricultural area caused children to have brain damage. Studies have linked chlorpyrifos to a wide range of developmental and neurological disorders, including lowered IQ, autism, stunting and Parkinson’s, and cancer. Nearly 61 million lbs of the chemical were applied between 1974 and 2017 in the four countries covered by the lawsuit. Lawyers for the case allege that as many as 100,000 people may need to dispose of their personal belongings as a result of contamination.
So although we may not know right now exactly what’s causing adults in America and Europe to burn less energy at rest, we can at least be sure of this: that the corporate sirensong of semaglutide and other such “wonder drugs” is a distraction from the real causes of obesity. And the more we listen, the less likely anything will change for the better.
